An airplane is conventionally provided with an ILS (instrument landing system) and a TIS (tunnel in the sky) for obtaining the deviation angle and the relative position of the target flight path from the airplane. The deviation angle and the relative position obtained with the ILS and the TIS are displayed on a PFD (primary flight display) or an ADI (attitude direction indicator), which is a display apparatus for displaying the flying situation of the aircraft, thereby assisting the pilot of the airplane to perform control for tracking the target flight path.
FIG. 7 shows an example conventional PFD 100. The PFD 100 shown in FIG. 7 shows ILS displays 102 and FD (flight director) command and bar displays 104, together with airplane reference symbols 101 that indicate the aircraft, which is an airplane.
The ILS displays 102 indicate the deviation angle (ILS display 102A) of the aircraft from a localizer and the deviation angle (ILS display 102B) of the aircraft from a glide slope. The example in FIG. 7 shows that the target flight path is located at the left side of the aircraft.
The FD-command and bar displays 104 indicate attitude (pitch angle and bank angle) commands for the aircraft for tracking the target flight path. Note that, in the example of FIG. 7, a bank-angle command display 104A gives an instruction to bank the aircraft left, and a pitch-angle command display 104B gives an instruction to lower the pitch of the aircraft.
Furthermore, PTL 1 discloses a flight-path display apparatus in which, when the display position of the flight path of the airplane is located outside the display range of an image combining panel included in a head-up display device, a target mark indicating the direction from the display range center of the image combining panel toward the flight path is displayed on the image combining panel. Note that the above-described flight path is composed of a plurality of path marks, and the path marks are inclined according to the attitude of the airframe estimated when the airframe is displayed on the path marks.